Field of the Invention
The present invention relates to wireless LANs, and more specifically, a method and apparatus that perform initial access over a wireless LAN.
Related Art
Recent wireless LAN technologies are evolving largely in three ways. Efforts to further increase transmission speed include IEEE (Institute of Electrical and Electronic Engineers) 802.11ac and IEEE 802.11ad as extensions to the existing WLAN evolution. IEEE802.11ad is a wireless LAN technique that employs a 60 GH band. Further, broad band wireless LAN utilizing a frequency band of less than 1 GHz is nowadays on the rise to enable transmission in a broader area than by the existing WLAN and such WLAN technologies include IEEE 802.11af utilizing a TVWS (TV White Space) band and IEEE 802.11ah utilizing a 900 MHz band. These standards primarily target expansion of extended range Wi-Fi services as well as smart grid and wide-area sensor networks. Further, the conventional WLAN MAC (Medium Access Control) techniques suffer from the issue that the initial link setup time is significantly increased in some cases. Standardization of IEEE 802.11ai is actively going on to address such issue to thus enable quick access from an STA to an AP.
IEEE 802.11ai is directed to an MAC technique that deals with a rapid authentication procedure to substantially save the initial setup and association time of WLAN and its standardization activities have been started with a normal task group since January 2011. To enable a quick access procedure, the IEEE 802.11ai task group goes on discussion for simplified procedures in the fields of AP discovery, network discovery, TSF (Time Synchronization Function) synchronization, authentication & association, merging with higher layers. Among others, procedure merging utilizing piggyback of DHCP (Dynamic Host Configuration Protocol)), optimization of full EAP (Extensible Authentication Protocol) using concurrent IP, and efficient selective AP (Access Point) scanning are actively under discussion.